Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1058 insertions, 0 deletions

diff --git a/src/encoding/xml/marshal.go b/src/encoding/xml/marshal.go
new file mode 100644
index 0000000..d8a04a9
--- /dev/null
+++ b/src/encoding/xml/marshal.go
@@ -0,0 +1,1058 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xml
+
+import (
+	"bufio"
+	"bytes"
+	"encoding"
+	"fmt"
+	"io"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+const (
+	// Header is a generic XML header suitable for use with the output of Marshal.
+	// This is not automatically added to any output of this package,
+	// it is provided as a convenience.
+	Header = `<?xml version="1.0" encoding="UTF-8"?>` + "\n"
+)
+
+// Marshal returns the XML encoding of v.
+//
+// Marshal handles an array or slice by marshaling each of the elements.
+// Marshal handles a pointer by marshaling the value it points at or, if the
+// pointer is nil, by writing nothing. Marshal handles an interface value by
+// marshaling the value it contains or, if the interface value is nil, by
+// writing nothing. Marshal handles all other data by writing one or more XML
+// elements containing the data.
+//
+// The name for the XML elements is taken from, in order of preference:
+//     - the tag on the XMLName field, if the data is a struct
+//     - the value of the XMLName field of type Name
+//     - the tag of the struct field used to obtain the data
+//     - the name of the struct field used to obtain the data
+//     - the name of the marshaled type
+//
+// The XML element for a struct contains marshaled elements for each of the
+// exported fields of the struct, with these exceptions:
+//     - the XMLName field, described above, is omitted.
+//     - a field with tag "-" is omitted.
+//     - a field with tag "name,attr" becomes an attribute with
+//       the given name in the XML element.
+//     - a field with tag ",attr" becomes an attribute with the
+//       field name in the XML element.
+//     - a field with tag ",chardata" is written as character data,
+//       not as an XML element.
+//     - a field with tag ",cdata" is written as character data
+//       wrapped in one or more <![CDATA[ ... ]]> tags, not as an XML element.
+//     - a field with tag ",innerxml" is written verbatim, not subject
+//       to the usual marshaling procedure.
+//     - a field with tag ",comment" is written as an XML comment, not
+//       subject to the usual marshaling procedure. It must not contain
+//       the "--" string within it.
+//     - a field with a tag including the "omitempty" option is omitted
+//       if the field value is empty. The empty values are false, 0, any
+//       nil pointer or interface value, and any array, slice, map, or
+//       string of length zero.
+//     - an anonymous struct field is handled as if the fields of its
+//       value were part of the outer struct.
+//     - a field implementing Marshaler is written by calling its MarshalXML
+//       method.
+//     - a field implementing encoding.TextMarshaler is written by encoding the
+//       result of its MarshalText method as text.
+//
+// If a field uses a tag "a>b>c", then the element c will be nested inside
+// parent elements a and b. Fields that appear next to each other that name
+// the same parent will be enclosed in one XML element.
+//
+// If the XML name for a struct field is defined by both the field tag and the
+// struct's XMLName field, the names must match.
+//
+// See MarshalIndent for an example.
+//
+// Marshal will return an error if asked to marshal a channel, function, or map.
+func Marshal(v interface{}) ([]byte, error) {
+	var b bytes.Buffer
+	if err := NewEncoder(&b).Encode(v); err != nil {
+		return nil, err
+	}
+	return b.Bytes(), nil
+}
+
+// Marshaler is the interface implemented by objects that can marshal
+// themselves into valid XML elements.
+//
+// MarshalXML encodes the receiver as zero or more XML elements.
+// By convention, arrays or slices are typically encoded as a sequence
+// of elements, one per entry.
+// Using start as the element tag is not required, but doing so
+// will enable Unmarshal to match the XML elements to the correct
+// struct field.
+// One common implementation strategy is to construct a separate
+// value with a layout corresponding to the desired XML and then
+// to encode it using e.EncodeElement.
+// Another common strategy is to use repeated calls to e.EncodeToken
+// to generate the XML output one token at a time.
+// The sequence of encoded tokens must make up zero or more valid
+// XML elements.
+type Marshaler interface {
+	MarshalXML(e *Encoder, start StartElement) error
+}
+
+// MarshalerAttr is the interface implemented by objects that can marshal
+// themselves into valid XML attributes.
+//
+// MarshalXMLAttr returns an XML attribute with the encoded value of the receiver.
+// Using name as the attribute name is not required, but doing so
+// will enable Unmarshal to match the attribute to the correct
+// struct field.
+// If MarshalXMLAttr returns the zero attribute Attr{}, no attribute
+// will be generated in the output.
+// MarshalXMLAttr is used only for struct fields with the
+// "attr" option in the field tag.
+type MarshalerAttr interface {
+	MarshalXMLAttr(name Name) (Attr, error)
+}
+
+// MarshalIndent works like Marshal, but each XML element begins on a new
+// indented line that starts with prefix and is followed by one or more
+// copies of indent according to the nesting depth.
+func MarshalIndent(v interface{}, prefix, indent string) ([]byte, error) {
+	var b bytes.Buffer
+	enc := NewEncoder(&b)
+	enc.Indent(prefix, indent)
+	if err := enc.Encode(v); err != nil {
+		return nil, err
+	}
+	return b.Bytes(), nil
+}
+
+// An Encoder writes XML data to an output stream.
+type Encoder struct {
+	p printer
+}
+
+// NewEncoder returns a new encoder that writes to w.
+func NewEncoder(w io.Writer) *Encoder {
+	e := &Encoder{printer{Writer: bufio.NewWriter(w)}}
+	e.p.encoder = e
+	return e
+}
+
+// Indent sets the encoder to generate XML in which each element
+// begins on a new indented line that starts with prefix and is followed by
+// one or more copies of indent according to the nesting depth.
+func (enc *Encoder) Indent(prefix, indent string) {
+	enc.p.prefix = prefix
+	enc.p.indent = indent
+}
+
+// Encode writes the XML encoding of v to the stream.
+//
+// See the documentation for Marshal for details about the conversion
+// of Go values to XML.
+//
+// Encode calls Flush before returning.
+func (enc *Encoder) Encode(v interface{}) error {
+	err := enc.p.marshalValue(reflect.ValueOf(v), nil, nil)
+	if err != nil {
+		return err
+	}
+	return enc.p.Flush()
+}
+
+// EncodeElement writes the XML encoding of v to the stream,
+// using start as the outermost tag in the encoding.
+//
+// See the documentation for Marshal for details about the conversion
+// of Go values to XML.
+//
+// EncodeElement calls Flush before returning.
+func (enc *Encoder) EncodeElement(v interface{}, start StartElement) error {
+	err := enc.p.marshalValue(reflect.ValueOf(v), nil, &start)
+	if err != nil {
+		return err
+	}
+	return enc.p.Flush()
+}
+
+var (
+	begComment  = []byte("<!--")
+	endComment  = []byte("-->")
+	endProcInst = []byte("?>")
+)
+
+// EncodeToken writes the given XML token to the stream.
+// It returns an error if StartElement and EndElement tokens are not properly matched.
+//
+// EncodeToken does not call Flush, because usually it is part of a larger operation
+// such as Encode or EncodeElement (or a custom Marshaler's MarshalXML invoked
+// during those), and those will call Flush when finished.
+// Callers that create an Encoder and then invoke EncodeToken directly, without
+// using Encode or EncodeElement, need to call Flush when finished to ensure
+// that the XML is written to the underlying writer.
+//
+// EncodeToken allows writing a ProcInst with Target set to "xml" only as the first token
+// in the stream.
+func (enc *Encoder) EncodeToken(t Token) error {
+
+	p := &enc.p
+	switch t := t.(type) {
+	case StartElement:
+		if err := p.writeStart(&t); err != nil {
+			return err
+		}
+	case EndElement:
+		if err := p.writeEnd(t.Name); err != nil {
+			return err
+		}
+	case CharData:
+		escapeText(p, t, false)
+	case Comment:
+		if bytes.Contains(t, endComment) {
+			return fmt.Errorf("xml: EncodeToken of Comment containing --> marker")
+		}
+		p.WriteString("<!--")
+		p.Write(t)
+		p.WriteString("-->")
+		return p.cachedWriteError()
+	case ProcInst:
+		// First token to be encoded which is also a ProcInst with target of xml
+		// is the xml declaration. The only ProcInst where target of xml is allowed.
+		if t.Target == "xml" && p.Buffered() != 0 {
+			return fmt.Errorf("xml: EncodeToken of ProcInst xml target only valid for xml declaration, first token encoded")
+		}
+		if !isNameString(t.Target) {
+			return fmt.Errorf("xml: EncodeToken of ProcInst with invalid Target")
+		}
+		if bytes.Contains(t.Inst, endProcInst) {
+			return fmt.Errorf("xml: EncodeToken of ProcInst containing ?> marker")
+		}
+		p.WriteString("<?")
+		p.WriteString(t.Target)
+		if len(t.Inst) > 0 {
+			p.WriteByte(' ')
+			p.Write(t.Inst)
+		}
+		p.WriteString("?>")
+	case Directive:
+		if !isValidDirective(t) {
+			return fmt.Errorf("xml: EncodeToken of Directive containing wrong < or > markers")
+		}
+		p.WriteString("<!")
+		p.Write(t)
+		p.WriteString(">")
+	default:
+		return fmt.Errorf("xml: EncodeToken of invalid token type")
+
+	}
+	return p.cachedWriteError()
+}
+
+// isValidDirective reports whether dir is a valid directive text,
+// meaning angle brackets are matched, ignoring comments and strings.
+func isValidDirective(dir Directive) bool {
+	var (
+		depth     int
+		inquote   uint8
+		incomment bool
+	)
+	for i, c := range dir {
+		switch {
+		case incomment:
+			if c == '>' {
+				if n := 1 + i - len(endComment); n >= 0 && bytes.Equal(dir[n:i+1], endComment) {
+					incomment = false
+				}
+			}
+			// Just ignore anything in comment
+		case inquote != 0:
+			if c == inquote {
+				inquote = 0
+			}
+			// Just ignore anything within quotes
+		case c == '\'' || c == '"':
+			inquote = c
+		case c == '<':
+			if i+len(begComment) < len(dir) && bytes.Equal(dir[i:i+len(begComment)], begComment) {
+				incomment = true
+			} else {
+				depth++
+			}
+		case c == '>':
+			if depth == 0 {
+				return false
+			}
+			depth--
+		}
+	}
+	return depth == 0 && inquote == 0 && !incomment
+}
+
+// Flush flushes any buffered XML to the underlying writer.
+// See the EncodeToken documentation for details about when it is necessary.
+func (enc *Encoder) Flush() error {
+	return enc.p.Flush()
+}
+
+type printer struct {
+	*bufio.Writer
+	encoder    *Encoder
+	seq        int
+	indent     string
+	prefix     string
+	depth      int
+	indentedIn bool
+	putNewline bool
+	attrNS     map[string]string // map prefix -> name space
+	attrPrefix map[string]string // map name space -> prefix
+	prefixes   []string
+	tags       []Name
+}
+
+// createAttrPrefix finds the name space prefix attribute to use for the given name space,
+// defining a new prefix if necessary. It returns the prefix.
+func (p *printer) createAttrPrefix(url string) string {
+	if prefix := p.attrPrefix[url]; prefix != "" {
+		return prefix
+	}
+
+	// The "http://www.w3.org/XML/1998/namespace" name space is predefined as "xml"
+	// and must be referred to that way.
+	// (The "http://www.w3.org/2000/xmlns/" name space is also predefined as "xmlns",
+	// but users should not be trying to use that one directly - that's our job.)
+	if url == xmlURL {
+		return xmlPrefix
+	}
+
+	// Need to define a new name space.
+	if p.attrPrefix == nil {
+		p.attrPrefix = make(map[string]string)
+		p.attrNS = make(map[string]string)
+	}
+
+	// Pick a name. We try to use the final element of the path
+	// but fall back to _.
+	prefix := strings.TrimRight(url, "/")
+	if i := strings.LastIndex(prefix, "/"); i >= 0 {
+		prefix = prefix[i+1:]
+	}
+	if prefix == "" || !isName([]byte(prefix)) || strings.Contains(prefix, ":") {
+		prefix = "_"
+	}
+	// xmlanything is reserved and any variant of it regardless of
+	// case should be matched, so:
+	//    (('X'|'x') ('M'|'m') ('L'|'l'))
+	// See Section 2.3 of https://www.w3.org/TR/REC-xml/
+	if len(prefix) >= 3 && strings.EqualFold(prefix[:3], "xml") {
+		prefix = "_" + prefix
+	}
+	if p.attrNS[prefix] != "" {
+		// Name is taken. Find a better one.
+		for p.seq++; ; p.seq++ {
+			if id := prefix + "_" + strconv.Itoa(p.seq); p.attrNS[id] == "" {
+				prefix = id
+				break
+			}
+		}
+	}
+
+	p.attrPrefix[url] = prefix
+	p.attrNS[prefix] = url
+
+	p.WriteString(`xmlns:`)
+	p.WriteString(prefix)
+	p.WriteString(`="`)
+	EscapeText(p, []byte(url))
+	p.WriteString(`" `)
+
+	p.prefixes = append(p.prefixes, prefix)
+
+	return prefix
+}
+
+// deleteAttrPrefix removes an attribute name space prefix.
+func (p *printer) deleteAttrPrefix(prefix string) {
+	delete(p.attrPrefix, p.attrNS[prefix])
+	delete(p.attrNS, prefix)
+}
+
+func (p *printer) markPrefix() {
+	p.prefixes = append(p.prefixes, "")
+}
+
+func (p *printer) popPrefix() {
+	for len(p.prefixes) > 0 {
+		prefix := p.prefixes[len(p.prefixes)-1]
+		p.prefixes = p.prefixes[:len(p.prefixes)-1]
+		if prefix == "" {
+			break
+		}
+		p.deleteAttrPrefix(prefix)
+	}
+}
+
+var (
+	marshalerType     = reflect.TypeOf((*Marshaler)(nil)).Elem()
+	marshalerAttrType = reflect.TypeOf((*MarshalerAttr)(nil)).Elem()
+	textMarshalerType = reflect.TypeOf((*encoding.TextMarshaler)(nil)).Elem()
+)
+
+// marshalValue writes one or more XML elements representing val.
+// If val was obtained from a struct field, finfo must have its details.
+func (p *printer) marshalValue(val reflect.Value, finfo *fieldInfo, startTemplate *StartElement) error {
+	if startTemplate != nil && startTemplate.Name.Local == "" {
+		return fmt.Errorf("xml: EncodeElement of StartElement with missing name")
+	}
+
+	if !val.IsValid() {
+		return nil
+	}
+	if finfo != nil && finfo.flags&fOmitEmpty != 0 && isEmptyValue(val) {
+		return nil
+	}
+
+	// Drill into interfaces and pointers.
+	// This can turn into an infinite loop given a cyclic chain,
+	// but it matches the Go 1 behavior.
+	for val.Kind() == reflect.Interface || val.Kind() == reflect.Ptr {
+		if val.IsNil() {
+			return nil
+		}
+		val = val.Elem()
+	}
+
+	kind := val.Kind()
+	typ := val.Type()
+
+	// Check for marshaler.
+	if val.CanInterface() && typ.Implements(marshalerType) {
+		return p.marshalInterface(val.Interface().(Marshaler), defaultStart(typ, finfo, startTemplate))
+	}
+	if val.CanAddr() {
+		pv := val.Addr()
+		if pv.CanInterface() && pv.Type().Implements(marshalerType) {
+			return p.marshalInterface(pv.Interface().(Marshaler), defaultStart(pv.Type(), finfo, startTemplate))
+		}
+	}
+
+	// Check for text marshaler.
+	if val.CanInterface() && typ.Implements(textMarshalerType) {
+		return p.marshalTextInterface(val.Interface().(encoding.TextMarshaler), defaultStart(typ, finfo, startTemplate))
+	}
+	if val.CanAddr() {
+		pv := val.Addr()
+		if pv.CanInterface() && pv.Type().Implements(textMarshalerType) {
+			return p.marshalTextInterface(pv.Interface().(encoding.TextMarshaler), defaultStart(pv.Type(), finfo, startTemplate))
+		}
+	}
+
+	// Slices and arrays iterate over the elements. They do not have an enclosing tag.
+	if (kind == reflect.Slice || kind == reflect.Array) && typ.Elem().Kind() != reflect.Uint8 {
+		for i, n := 0, val.Len(); i < n; i++ {
+			if err := p.marshalValue(val.Index(i), finfo, startTemplate); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+
+	tinfo, err := getTypeInfo(typ)
+	if err != nil {
+		return err
+	}
+
+	// Create start element.
+	// Precedence for the XML element name is:
+	// 0. startTemplate
+	// 1. XMLName field in underlying struct;
+	// 2. field name/tag in the struct field; and
+	// 3. type name
+	var start StartElement
+
+	if startTemplate != nil {
+		start.Name = startTemplate.Name
+		start.Attr = append(start.Attr, startTemplate.Attr...)
+	} else if tinfo.xmlname != nil {
+		xmlname := tinfo.xmlname
+		if xmlname.name != "" {
+			start.Name.Space, start.Name.Local = xmlname.xmlns, xmlname.name
+		} else {
+			fv := xmlname.value(val, dontInitNilPointers)
+			if v, ok := fv.Interface().(Name); ok && v.Local != "" {
+				start.Name = v
+			}
+		}
+	}
+	if start.Name.Local == "" && finfo != nil {
+		start.Name.Space, start.Name.Local = finfo.xmlns, finfo.name
+	}
+	if start.Name.Local == "" {
+		name := typ.Name()
+		if name == "" {
+			return &UnsupportedTypeError{typ}
+		}
+		start.Name.Local = name
+	}
+
+	// Attributes
+	for i := range tinfo.fields {
+		finfo := &tinfo.fields[i]
+		if finfo.flags&fAttr == 0 {
+			continue
+		}
+		fv := finfo.value(val, dontInitNilPointers)
+
+		if finfo.flags&fOmitEmpty != 0 && isEmptyValue(fv) {
+			continue
+		}
+
+		if fv.Kind() == reflect.Interface && fv.IsNil() {
+			continue
+		}
+
+		name := Name{Space: finfo.xmlns, Local: finfo.name}
+		if err := p.marshalAttr(&start, name, fv); err != nil {
+			return err
+		}
+	}
+
+	if err := p.writeStart(&start); err != nil {
+		return err
+	}
+
+	if val.Kind() == reflect.Struct {
+		err = p.marshalStruct(tinfo, val)
+	} else {
+		s, b, err1 := p.marshalSimple(typ, val)
+		if err1 != nil {
+			err = err1
+		} else if b != nil {
+			EscapeText(p, b)
+		} else {
+			p.EscapeString(s)
+		}
+	}
+	if err != nil {
+		return err
+	}
+
+	if err := p.writeEnd(start.Name); err != nil {
+		return err
+	}
+
+	return p.cachedWriteError()
+}
+
+// marshalAttr marshals an attribute with the given name and value, adding to start.Attr.
+func (p *printer) marshalAttr(start *StartElement, name Name, val reflect.Value) error {
+	if val.CanInterface() && val.Type().Implements(marshalerAttrType) {
+		attr, err := val.Interface().(MarshalerAttr).MarshalXMLAttr(name)
+		if err != nil {
+			return err
+		}
+		if attr.Name.Local != "" {
+			start.Attr = append(start.Attr, attr)
+		}
+		return nil
+	}
+
+	if val.CanAddr() {
+		pv := val.Addr()
+		if pv.CanInterface() && pv.Type().Implements(marshalerAttrType) {
+			attr, err := pv.Interface().(MarshalerAttr).MarshalXMLAttr(name)
+			if err != nil {
+				return err
+			}
+			if attr.Name.Local != "" {
+				start.Attr = append(start.Attr, attr)
+			}
+			return nil
+		}
+	}
+
+	if val.CanInterface() && val.Type().Implements(textMarshalerType) {
+		text, err := val.Interface().(encoding.TextMarshaler).MarshalText()
+		if err != nil {
+			return err
+		}
+		start.Attr = append(start.Attr, Attr{name, string(text)})
+		return nil
+	}
+
+	if val.CanAddr() {
+		pv := val.Addr()
+		if pv.CanInterface() && pv.Type().Implements(textMarshalerType) {
+			text, err := pv.Interface().(encoding.TextMarshaler).MarshalText()
+			if err != nil {
+				return err
+			}
+			start.Attr = append(start.Attr, Attr{name, string(text)})
+			return nil
+		}
+	}
+
+	// Dereference or skip nil pointer, interface values.
+	switch val.Kind() {
+	case reflect.Ptr, reflect.Interface:
+		if val.IsNil() {
+			return nil
+		}
+		val = val.Elem()
+	}
+
+	// Walk slices.
+	if val.Kind() == reflect.Slice && val.Type().Elem().Kind() != reflect.Uint8 {
+		n := val.Len()
+		for i := 0; i < n; i++ {
+			if err := p.marshalAttr(start, name, val.Index(i)); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+
+	if val.Type() == attrType {
+		start.Attr = append(start.Attr, val.Interface().(Attr))
+		return nil
+	}
+
+	s, b, err := p.marshalSimple(val.Type(), val)
+	if err != nil {
+		return err
+	}
+	if b != nil {
+		s = string(b)
+	}
+	start.Attr = append(start.Attr, Attr{name, s})
+	return nil
+}
+
+// defaultStart returns the default start element to use,
+// given the reflect type, field info, and start template.
+func defaultStart(typ reflect.Type, finfo *fieldInfo, startTemplate *StartElement) StartElement {
+	var start StartElement
+	// Precedence for the XML element name is as above,
+	// except that we do not look inside structs for the first field.
+	if startTemplate != nil {
+		start.Name = startTemplate.Name
+		start.Attr = append(start.Attr, startTemplate.Attr...)
+	} else if finfo != nil && finfo.name != "" {
+		start.Name.Local = finfo.name
+		start.Name.Space = finfo.xmlns
+	} else if typ.Name() != "" {
+		start.Name.Local = typ.Name()
+	} else {
+		// Must be a pointer to a named type,
+		// since it has the Marshaler methods.
+		start.Name.Local = typ.Elem().Name()
+	}
+	return start
+}
+
+// marshalInterface marshals a Marshaler interface value.
+func (p *printer) marshalInterface(val Marshaler, start StartElement) error {
+	// Push a marker onto the tag stack so that MarshalXML
+	// cannot close the XML tags that it did not open.
+	p.tags = append(p.tags, Name{})
+	n := len(p.tags)
+
+	err := val.MarshalXML(p.encoder, start)
+	if err != nil {
+		return err
+	}
+
+	// Make sure MarshalXML closed all its tags. p.tags[n-1] is the mark.
+	if len(p.tags) > n {
+		return fmt.Errorf("xml: %s.MarshalXML wrote invalid XML: <%s> not closed", receiverType(val), p.tags[len(p.tags)-1].Local)
+	}
+	p.tags = p.tags[:n-1]
+	return nil
+}
+
+// marshalTextInterface marshals a TextMarshaler interface value.
+func (p *printer) marshalTextInterface(val encoding.TextMarshaler, start StartElement) error {
+	if err := p.writeStart(&start); err != nil {
+		return err
+	}
+	text, err := val.MarshalText()
+	if err != nil {
+		return err
+	}
+	EscapeText(p, text)
+	return p.writeEnd(start.Name)
+}
+
+// writeStart writes the given start element.
+func (p *printer) writeStart(start *StartElement) error {
+	if start.Name.Local == "" {
+		return fmt.Errorf("xml: start tag with no name")
+	}
+
+	p.tags = append(p.tags, start.Name)
+	p.markPrefix()
+
+	p.writeIndent(1)
+	p.WriteByte('<')
+	p.WriteString(start.Name.Local)
+
+	if start.Name.Space != "" {
+		p.WriteString(` xmlns="`)
+		p.EscapeString(start.Name.Space)
+		p.WriteByte('"')
+	}
+
+	// Attributes
+	for _, attr := range start.Attr {
+		name := attr.Name
+		if name.Local == "" {
+			continue
+		}
+		p.WriteByte(' ')
+		if name.Space != "" {
+			p.WriteString(p.createAttrPrefix(name.Space))
+			p.WriteByte(':')
+		}
+		p.WriteString(name.Local)
+		p.WriteString(`="`)
+		p.EscapeString(attr.Value)
+		p.WriteByte('"')
+	}
+	p.WriteByte('>')
+	return nil
+}
+
+func (p *printer) writeEnd(name Name) error {
+	if name.Local == "" {
+		return fmt.Errorf("xml: end tag with no name")
+	}
+	if len(p.tags) == 0 || p.tags[len(p.tags)-1].Local == "" {
+		return fmt.Errorf("xml: end tag </%s> without start tag", name.Local)
+	}
+	if top := p.tags[len(p.tags)-1]; top != name {
+		if top.Local != name.Local {
+			return fmt.Errorf("xml: end tag </%s> does not match start tag <%s>", name.Local, top.Local)
+		}
+		return fmt.Errorf("xml: end tag </%s> in namespace %s does not match start tag <%s> in namespace %s", name.Local, name.Space, top.Local, top.Space)
+	}
+	p.tags = p.tags[:len(p.tags)-1]
+
+	p.writeIndent(-1)
+	p.WriteByte('<')
+	p.WriteByte('/')
+	p.WriteString(name.Local)
+	p.WriteByte('>')
+	p.popPrefix()
+	return nil
+}
+
+func (p *printer) marshalSimple(typ reflect.Type, val reflect.Value) (string, []byte, error) {
+	switch val.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return strconv.FormatInt(val.Int(), 10), nil, nil
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return strconv.FormatUint(val.Uint(), 10), nil, nil
+	case reflect.Float32, reflect.Float64:
+		return strconv.FormatFloat(val.Float(), 'g', -1, val.Type().Bits()), nil, nil
+	case reflect.String:
+		return val.String(), nil, nil
+	case reflect.Bool:
+		return strconv.FormatBool(val.Bool()), nil, nil
+	case reflect.Array:
+		if typ.Elem().Kind() != reflect.Uint8 {
+			break
+		}
+		// [...]byte
+		var bytes []byte
+		if val.CanAddr() {
+			bytes = val.Slice(0, val.Len()).Bytes()
+		} else {
+			bytes = make([]byte, val.Len())
+			reflect.Copy(reflect.ValueOf(bytes), val)
+		}
+		return "", bytes, nil
+	case reflect.Slice:
+		if typ.Elem().Kind() != reflect.Uint8 {
+			break
+		}
+		// []byte
+		return "", val.Bytes(), nil
+	}
+	return "", nil, &UnsupportedTypeError{typ}
+}
+
+var ddBytes = []byte("--")
+
+// indirect drills into interfaces and pointers, returning the pointed-at value.
+// If it encounters a nil interface or pointer, indirect returns that nil value.
+// This can turn into an infinite loop given a cyclic chain,
+// but it matches the Go 1 behavior.
+func indirect(vf reflect.Value) reflect.Value {
+	for vf.Kind() == reflect.Interface || vf.Kind() == reflect.Ptr {
+		if vf.IsNil() {
+			return vf
+		}
+		vf = vf.Elem()
+	}
+	return vf
+}
+
+func (p *printer) marshalStruct(tinfo *typeInfo, val reflect.Value) error {
+	s := parentStack{p: p}
+	for i := range tinfo.fields {
+		finfo := &tinfo.fields[i]
+		if finfo.flags&fAttr != 0 {
+			continue
+		}
+		vf := finfo.value(val, dontInitNilPointers)
+		if !vf.IsValid() {
+			// The field is behind an anonymous struct field that's
+			// nil. Skip it.
+			continue
+		}
+
+		switch finfo.flags & fMode {
+		case fCDATA, fCharData:
+			emit := EscapeText
+			if finfo.flags&fMode == fCDATA {
+				emit = emitCDATA
+			}
+			if err := s.trim(finfo.parents); err != nil {
+				return err
+			}
+			if vf.CanInterface() && vf.Type().Implements(textMarshalerType) {
+				data, err := vf.Interface().(encoding.TextMarshaler).MarshalText()
+				if err != nil {
+					return err
+				}
+				if err := emit(p, data); err != nil {
+					return err
+				}
+				continue
+			}
+			if vf.CanAddr() {
+				pv := vf.Addr()
+				if pv.CanInterface() && pv.Type().Implements(textMarshalerType) {
+					data, err := pv.Interface().(encoding.TextMarshaler).MarshalText()
+					if err != nil {
+						return err
+					}
+					if err := emit(p, data); err != nil {
+						return err
+					}
+					continue
+				}
+			}
+
+			var scratch [64]byte
+			vf = indirect(vf)
+			switch vf.Kind() {
+			case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+				if err := emit(p, strconv.AppendInt(scratch[:0], vf.Int(), 10)); err != nil {
+					return err
+				}
+			case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+				if err := emit(p, strconv.AppendUint(scratch[:0], vf.Uint(), 10)); err != nil {
+					return err
+				}
+			case reflect.Float32, reflect.Float64:
+				if err := emit(p, strconv.AppendFloat(scratch[:0], vf.Float(), 'g', -1, vf.Type().Bits())); err != nil {
+					return err
+				}
+			case reflect.Bool:
+				if err := emit(p, strconv.AppendBool(scratch[:0], vf.Bool())); err != nil {
+					return err
+				}
+			case reflect.String:
+				if err := emit(p, []byte(vf.String())); err != nil {
+					return err
+				}
+			case reflect.Slice:
+				if elem, ok := vf.Interface().([]byte); ok {
+					if err := emit(p, elem); err != nil {
+						return err
+					}
+				}
+			}
+			continue
+
+		case fComment:
+			if err := s.trim(finfo.parents); err != nil {
+				return err
+			}
+			vf = indirect(vf)
+			k := vf.Kind()
+			if !(k == reflect.String || k == reflect.Slice && vf.Type().Elem().Kind() == reflect.Uint8) {
+				return fmt.Errorf("xml: bad type for comment field of %s", val.Type())
+			}
+			if vf.Len() == 0 {
+				continue
+			}
+			p.writeIndent(0)
+			p.WriteString("<!--")
+			dashDash := false
+			dashLast := false
+			switch k {
+			case reflect.String:
+				s := vf.String()
+				dashDash = strings.Contains(s, "--")
+				dashLast = s[len(s)-1] == '-'
+				if !dashDash {
+					p.WriteString(s)
+				}
+			case reflect.Slice:
+				b := vf.Bytes()
+				dashDash = bytes.Contains(b, ddBytes)
+				dashLast = b[len(b)-1] == '-'
+				if !dashDash {
+					p.Write(b)
+				}
+			default:
+				panic("can't happen")
+			}
+			if dashDash {
+				return fmt.Errorf(`xml: comments must not contain "--"`)
+			}
+			if dashLast {
+				// "--->" is invalid grammar. Make it "- -->"
+				p.WriteByte(' ')
+			}
+			p.WriteString("-->")
+			continue
+
+		case fInnerXML:
+			vf = indirect(vf)
+			iface := vf.Interface()
+			switch raw := iface.(type) {
+			case []byte:
+				p.Write(raw)
+				continue
+			case string:
+				p.WriteString(raw)
+				continue
+			}
+
+		case fElement, fElement | fAny:
+			if err := s.trim(finfo.parents); err != nil {
+				return err
+			}
+			if len(finfo.parents) > len(s.stack) {
+				if vf.Kind() != reflect.Ptr && vf.Kind() != reflect.Interface || !vf.IsNil() {
+					if err := s.push(finfo.parents[len(s.stack):]); err != nil {
+						return err
+					}
+				}
+			}
+		}
+		if err := p.marshalValue(vf, finfo, nil); err != nil {
+			return err
+		}
+	}
+	s.trim(nil)
+	return p.cachedWriteError()
+}
+
+// return the bufio Writer's cached write error
+func (p *printer) cachedWriteError() error {
+	_, err := p.Write(nil)
+	return err
+}
+
+func (p *printer) writeIndent(depthDelta int) {
+	if len(p.prefix) == 0 && len(p.indent) == 0 {
+		return
+	}
+	if depthDelta < 0 {
+		p.depth--
+		if p.indentedIn {
+			p.indentedIn = false
+			return
+		}
+		p.indentedIn = false
+	}
+	if p.putNewline {
+		p.WriteByte('\n')
+	} else {
+		p.putNewline = true
+	}
+	if len(p.prefix) > 0 {
+		p.WriteString(p.prefix)
+	}
+	if len(p.indent) > 0 {
+		for i := 0; i < p.depth; i++ {
+			p.WriteString(p.indent)
+		}
+	}
+	if depthDelta > 0 {
+		p.depth++
+		p.indentedIn = true
+	}
+}
+
+type parentStack struct {
+	p     *printer
+	stack []string
+}
+
+// trim updates the XML context to match the longest common prefix of the stack
+// and the given parents. A closing tag will be written for every parent
+// popped. Passing a zero slice or nil will close all the elements.
+func (s *parentStack) trim(parents []string) error {
+	split := 0
+	for ; split < len(parents) && split < len(s.stack); split++ {
+		if parents[split] != s.stack[split] {
+			break
+		}
+	}
+	for i := len(s.stack) - 1; i >= split; i-- {
+		if err := s.p.writeEnd(Name{Local: s.stack[i]}); err != nil {
+			return err
+		}
+	}
+	s.stack = s.stack[:split]
+	return nil
+}
+
+// push adds parent elements to the stack and writes open tags.
+func (s *parentStack) push(parents []string) error {
+	for i := 0; i < len(parents); i++ {
+		if err := s.p.writeStart(&StartElement{Name: Name{Local: parents[i]}}); err != nil {
+			return err
+		}
+	}
+	s.stack = append(s.stack, parents...)
+	return nil
+}
+
+// UnsupportedTypeError is returned when Marshal encounters a type
+// that cannot be converted into XML.
+type UnsupportedTypeError struct {
+	Type reflect.Type
+}
+
+func (e *UnsupportedTypeError) Error() string {
+	return "xml: unsupported type: " + e.Type.String()
+}
+
+func isEmptyValue(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
+		return v.Len() == 0
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Interface, reflect.Ptr:
+		return v.IsNil()
+	}
+	return false
+}